Answer:
x=3
Step-by-step explanation:
We are taking 2 times the sum ( addition) of 18 and x
2 ( 18+x) = 42
Divide each side by 2
2 /2 ( 18+x) = 42/2
18+x = 21
Subtract 18 from each side
18+x-18 = 21-18
x = 3
